Automatic set-up electroerosion machining method

ABSTRACT

Electroerosion machining (EDM or ECM) is carried out with a minimum of manual intervention. Under control of recorded data an electronic control system utilizing control logic directs the set-up operations as well as the actual machining process. The operations automatically (i.e., without the necessity of manual intervention) include loading and removal of workpieces and electrode material, trueing up of the workpiece (which may be by providing a transformation of the data rather than by adjusting the position of the workpiece), making starting bores, threading the electrode through a starting bore, applying a low melting alloy or other conducting adhesive to cement a core in the process of being cut out by machining, cutting the electrode after completing a starting bore and joining electrode ends after rethreading in a new starting bore. In threading the electrode it may be pushed simply or with the support of a surrounding jet of pressure medium, or it may be pulled by a grapple member.



1. Method for electroerosion machining a workpiece having a startingbore by using as the machining tool a long drawn out flexible electrodecapable of being gradually dispensed, comprising the steps of: aligningsaid starting bore (9) of said workpiece (5) with an unencumberedstraight line path provided for said electrode (4) by an electrode driveand guiding system (7); dispensing said electrode (4) from an electrodesupply by means of said electrode drive and guiding system (7);threading said electrode (4) automatically by propelling it by saidsystem in said straight line path into, through and out beyond said bore(9) of said workpiece (5) until the end of the electrode becomes firmlyengaged in transport means (79) of a take-up mechanism (71) of saidelectrode drive and guiding system; and then dispensing said electrodegradually through said workpiece (5) and said take-up mechanism (71) ofsaid system (7) while applying electroerosion voltage thereto relativeto said workpiece and subjecting said electrode and workpiece torelative movement under control of an automatic electronic machiningdrive system to machine a predetermined contour (8) in said workpiece.2. Method according to claim 1, in which during the threading step theend of said electrode emerging from said bore is grasped by a grapplemeans (13) and pulled thereby until it reaches the transport means (79)of said take-up mechanism (71) (FIG. 3).
 3. Method according to claim 1,in which during the threading step the end of said electrode (4) isgrasped by a grapple means (13) and pulled through said bore (9) of saidworkpiece (5) until it reaches the transport means (79) of said take-upmechanism (71) (FIGS. 4 and 5).
 4. Method according to claim 1, in whichduring the threading step said electrode (4) is pushed by pushing means(81,82,83,84) projecting a pressure medium for directing said electrode(4) through said bore (9) of said workpiece (5) until the end of saidelectrode reaches the transport means (79) of said take-up mechanism(71) (FIG. 6).
 5. Method for electroerosion machining a workpiece havinga starting bore, by using a filamentary dispensable electrode as themachining tool, comprising the steps of: dispensing said electrode (4)from an electrode supply by means of an electrode drive and guidingsystem (7); threading said electrode (4) by propelling it by said systeminto and through said bore (9) of said workpiece (5) until the end ofthe electrode reaches the immediate vicinity of another electrode piececonnected to the take-up mechanism (71) of said drive and guiding system(7); connecting the dispensed electrode to said other electrode piece;and then dispensing said electrode through said workpiecE (5) and saidtake-up mechanism (71) of said system (7) while applying electroerosionvoltage thereto and subjecting said electrode and workpiece to relativemovement under the control of an automatic electronic machining drivesystem to machine a predetermined contour (8) in said workpiece. 6.Method according to claim 2 in which after said contour (8) is machined,said electrode (4): is held on both sides of said workpiece (5), isthereafter cut on one side of said workpiece, after which one severedpiece of said electrode is then held further, while the other is removedfrom said workpiece; thereafter a new starting bore (9) of saidworkpiece (5) is positioned for receiving said electrode, after whichthe threading of said electrode is repeated through the new startingbore and the connecting step is then repeated with the end of the newlythreaded electrode and the other severed piece, after which a newcontour, beginning at said new starting bore, is machined under thecontrol of said automatic electronic machining drive system; during eachsaid threading step said electrode being grasped as it emerges from saidbore by a grapple member (13) and pulled thereby until it engages aconnecting device (12) of said take-up mechanism (71) of said drive andguiding system (7) (FIG. 3).
 7. Method according to claim 2 in whichafter said contour (8) is machined, said electrode (4): is held on bothsides of said workpiece (5), is thereafter cut on one side of saidworkpiece, after which one severed piece of said electrode is then heldfurther, while the other is removed from said workpiece; thereafter anew starting bore (9) of said workpiece (5) is positioned for receivingsaid electrode, after which the threading of said electrode is repeatedthrough the new starting bore and the connecting step is then repeatedwith the end of the newly threaded electrode and the held severed piece,after which a new contour, beginning at said new starting bore, ismachined under the control of said automatic electronic machining drivesystem; during each said threading steps the end of said electrode beinggrasped by a grapple member (13) and pulled through said bore (9) ofsaid workpiece (5) until it engages a connection device (12) of saidtake-up mechanism (71) of said drive and guiding system (7) (FIG. 4). 8.Method according to claim 2, in which after said contour (8) ismachined, said electrode (4): is held on both sides of said workpiece(5); is thereafter cut on the electrode supply side of said workpiece;afer which the severed piece of said electrode which is in the bore ofsaid workpiece is removed from said workpiece while the other severedpiece is clamped in place; thereafter a new starting bore (9) of saidworkpiece (5) is positioned for receiving said electrode; after whichthe threading of said electrode is repeated by propelling the severedpiece of said electrode which was removed from the workpiece through thenew starting bore and the connecting step is then repeated by connectingthe end of the severed electrode that was so propelled with the othersevered piece by a connecting operation performed on the electrodesupply side of (72) said workpiece (FIG. 5), after which a new contour,beginning at said new starting bore, is machined under the control ofsaid automatic electronic machining drive system.
 9. Method according toclaim 2, in which after said contour (8) is machined, said electrode(4): is held clamped and is cut on one side of said workpiece (5); oneend of the electrode produced by the said cutting remains clamped; theother end produced by the said cutting is pulled out of said workpiece(5); thereafter a new starting bore (9) in the workpiece (5) ispositioned for receiving the severed electrode (4); thereafter theelectrode end that was pulled out of the workpiece is pushed through thelast-mentioned starting bore (9) By means of a pressure medium and, onreaching the take-up side of said electrode drive and guiding system (7)is joined with the first mentioned end of said electrode that in themeanwhile has been clamped (FIG. 6).